@article { WOS:000704665100001,
title = {Asymmetric Blockade and Multiqubit Gates via Dipole-Dipole Interactions},
journal = {Phys. Rev. Lett.},
volume = {127},
number = {12},
year = {2021},
month = {SEP 17},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {Because of their strong and tunable interactions, Rydberg atoms can be used to realize fast two-qubit entangling gates. We propose a generalization of a generic two-qubit Rydberg-blockade gate to multiqubit Rydberg-blockade gates that involve both many control qubits and many target qubits simultaneously. This is achieved by using strong microwave fields to dress nearby Rydberg states, leading to asymmetric blockade in which control-target interactions are much stronger than control-control and target-target interactions. The implementation of these multiqubit gates can drastically simplify both quantum algorithms and state preparation. To illustrate this, we show that a 25-atom Greenberger-Horne-Zeilinger state can be created using only three gates with an error of 5.8\%.},
issn = {0031-9007},
doi = {10.1103/PhysRevLett.127.120501},
author = {Young, Jeremy T. and Bienias, Przemyslaw and Belyansky, Ron and Kaufman, Adam M. and Gorshkov, V, Alexey}
}
@article { WOS:000704077500001,
title = {Complexity of Fermionic Dissipative Interactions and Applications to Quantum Computing},
journal = {PRX Quantum},
volume = {2},
number = {3},
year = {2021},
month = {SEP 24},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {Interactions between particles are usually a resource for quantum computing, making quantum many-body systems intractable by any known classical algorithm. In contrast, noise is typically considered as being inimical to quantum many-body correlations, ultimately leading the system to a classically tractable state. This work shows that noise represented by two-body processes, such as pair loss, plays the same role as many-body interactions and makes otherwise classically simulable systems universal for quantum computing. We analyze such processes in detail and establish a complexity transition between simulable and nonsimulable systems as a function of a tuning parameter. We determine important classes of simulable and nonsimulable two-body dissipation. Finally, we show how using resonant dissipation in cold atoms can enhance the performance of two-qubit gates.},
doi = {10.1103/PRXQuantum.2.030350},
author = {Shtanko, Oles and Deshpande, Abhinav and Julienne, Paul S. and Gorshkov, V, Alexey}
}
@article {curtis_critical_2021,
title = {Critical theory for the breakdown of photon blockade},
journal = {Phys. Rev. Res.},
volume = {3},
number = {2},
year = {2021},
note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article},
abstract = {Photon blockade is the result of the interplay between the quantized nature of light and strong optical nonlinearities, whereby strong photon-photon repulsion prevents a quantum optical system from absorbing multiple photons. We theoretically study a single atom coupled to the light field, described by the resonantly driven Jaynes-Cummings model, in which case the photon blockade breaks down in a second-order phase transition at a critical drive strength. We show that this transition is associated to the spontaneous breaking of an antiunitary PT symmetry. Within a semiclassical approximation, we calculate the expectation values of observables in the steady state. We then move beyond the semiclassical approximation and approach the critical point from the disordered (blockaded) phase by reducing the Lindblad quantum master equation to a classical rate equation that we solve. The width of the steady-state distribution in Fock space is found to diverge as we approach the critical point with a simple power law, allowing us to calculate the critical scaling of steady-state observables without invoking mean-field theory. We propose a simple physical toy model for biased diffusion in the space of occupation numbers, which captures the universal properties of the steady state. We list several experimental platforms where this phenomenon may be observed.},
doi = {10.1103/PhysRevResearch.3.023062},
author = {Curtis, Jonathan B. and Boettcher, Igor and Young, Jeremy T. and Maghrebi, Mohammad F. and Carmichael, Howard and Gorshkov, V, Alexey and Foss-Feig, Michael}
}
@article { WOS:000712467500001,
title = {Feedback-stabilized dynamical steady states in the Bose-Hubbard model},
journal = {Phys. Rev. Res.},
volume = {3},
number = {4},
year = {2021},
month = {OCT 27},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {The implementation of a combination of continuous weak measurement and classical feedback provides a powerful tool for controlling the evolution of quantum systems. In this paper, we investigate the potential of this approach from three perspectives. First, we consider a double-well system in the classical large-atom-number limit, deriving the exact equations of motion in the presence of feedback. Second, we consider the same system in the limit of small atom number, revealing the effect that quantum fluctuations have on the feedback scheme. Finally, we explore the behavior of modest-sized Hubbard chains using exact numerics, demonstrating the near-deterministic preparation of number states, a tradeoff between local and nonlocal feedback for state preparation, and evidence of a feedback-driven symmetry-breaking phase transition.},
doi = {10.1103/PhysRevResearch.3.043075},
author = {Young, Jeremy T. and Gorshkov, V, Alexey and Spielman, I. B.}
}
@article { WOS:000693643600008,
title = {Frustration-induced anomalous transport and strong photon decay in waveguide QED},
journal = {Phys. Rev. Res.},
volume = {3},
number = {3},
year = {2021},
month = {SEP 7},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {We study the propagation of photons in a one-dimensional environment consisting of two noninteracting species of photons frustratingly coupled to a single spin 1/2. The ultrastrong frustrated coupling leads to an extreme mixing of the light and matter degrees of freedom, resulting in the disintegration of the spin and a breakdown of the {\textquoteleft}{\textquoteleft}dressed-spin,{{\textquoteright}{\textquoteright}} or polaron, description. Using a combination of numerical and analytical methods, we show that the elastic response becomes increasingly weak at the effective spin frequency, showing instead an increasingly strong and broadband response at higher energies. We also show that the photons can decay into multiple photons of smaller energies. The total probability of these inelastic processes can be as large as the total elastic scattering rate, or half of the total scattering rate, which is as large as it can be. The frustrated spin induces strong anisotropic photon-photon interactions that are dominated by interspecies interactions. Our results are relevant to state-of-the-art circuit and cavity quantum electrodynamics experiments.},
doi = {10.1103/PhysRevResearch.3.L032058},
author = {Belyansky, Ron and Whitsitt, Seth and Lundgren, Rex and Wang, Yidan and Vrajitoarea, Andrei and Houck, Andrew A. and Gorshkov, V, Alexey}
}
@article { WOS:000646067200012,
title = {Optimal measurement of field properties with quantum sensor networks},
journal = {Phys. Rev. A},
volume = {103},
number = {3},
year = {2021},
month = {MAR 29},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {We consider a quantum sensor network of qubit sensors coupled to a field f (x; theta) analytically parameterized by the vector of parameters theta. The qubit sensors are fixed at positions x(1), ..., x(d). While the functional form of f (x; theta) is known, the parameters theta are not. We derive saturable bounds on the precision of measuring an arbitrary analytic function q(theta) of these parameters and construct the optimal protocols that achieve these bounds. Our results are obtained from a combination of techniques from quantum information theory and duality theorems for linear programming. They can be applied to many problems, including optimal placement of quantum sensors, field interpolation, and the measurement of functionals of parametrized fields.},
issn = {2469-9926},
doi = {10.1103/PhysRevA.103.L030601},
author = {Qian, Timothy and Bringewatt, Jacob and Boettcher, Igor and Bienias, Przemyslaw and Gorshkov, V, Alexey}
}
@article { WOS:000669569500009,
title = {Protocols for estimating multiple functions with quantum sensor networks: Geometry and performance},
journal = {Phys. Rev. Res.},
volume = {3},
number = {3},
year = {2021},
month = {JUL 2},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {We consider the problem of estimating multiple analytic functions of a set of local parameters via qubit sensors in a quantum sensor network. To address this problem, we highlight a generalization of the sensor symmetric performance bounds of Rubio et al., {[}J. Phys. A 53, 344001 (2020)] and develop an optimized sequential protocol for measuring such functions. We compare the performance of both approaches to one another and to local protocols that do not utilize quantum entanglement, emphasizing the geometric significance of the coefficient vectors of the measured functions in determining the best choice of measurement protocol. We show that, in many cases, especially for a large number of sensors, the optimized sequential protocol results in more accurate measurements than the other strategies. In addition, in contrast to the sensor symmetric approach, the sequential protocol is known to always be explicitly implementable. The sequential protocol is very general and has a wide range of metrological applications.},
doi = {10.1103/PhysRevResearch.3.033011},
author = {Bringewatt, Jacob and Boettcher, Igor and Niroula, Pradeep and Bienias, Przemyslaw and Gorshkov, V, Alexey}
}
@article { WOS:000674685900001,
title = {Quantum Computer Systems for Scientific Discovery},
journal = {PRX Quantum},
volume = {2},
number = {1},
year = {2021},
month = {FEB 24},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {The great promise of quantum computers comes with the dual challenges of building them and finding their useful applications. We argue that these two challenges should be considered together, by codesigning full-stack quantum computer systems along with their applications in order to hasten their development and potential for scientific discovery. In this context, we identify scientific and community needs, opportunities, a sampling of a few use case studies, and significant challenges for the development of quantum computers for science over the next 2-10 years. This document is written by a community of university, national laboratory, and industrial researchers in the field of Quantum Information Science and Technology, and is based on a summary from a U.S. National Science Foundation workshop on Quantum Computing held on October 21-22, 2019 in Alexandria, VA.},
doi = {10.1103/PRXQuantum.2.017001},
author = {Alexeev, Yuri and Bacon, Dave and Brown, Kenneth R. and Calderbank, Robert and Carr, Lincoln D. and Chong, Frederic T. and DeMarco, Brian and Englund, Dirk and Farhi, Edward and Fefferman, Bill and Gorshkov, V, Alexey and Houck, Andrew and Kim, Jungsang and Kimmel, Shelby and Lange, Michael and Lloyd, Seth and Lukin, Mikhail D. and Maslov, Dmitri and Maunz, Peter and Monroe, Christopher and Preskill, John and Roetteler, Martin and Savage, Martin J. and Thompson, Jeff}
}
@article { WOS:000655928700001,
title = {Quench Dynamics of a Fermi Gas with Strong Nonlocal Interactions},
journal = {Phys. Rev. X},
volume = {11},
number = {2},
year = {2021},
month = {MAY 17},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {We induce strong nonlocal interactions in a 2D Fermi gas in an optical lattice using Rydberg dressing. The system is approximately described by a t - V model on a square lattice where the fermions experience isotropic nearest-neighbor interactions and are free to hop only along one direction. We measure the interactions using many-body Ramsey interferometry and study the lifetime of the gas in the presence of tunneling, finding that tunneling does not reduce the lifetime. To probe the interplay of nonlocal interactions with tunneling, we investigate the short-time-relaxation dynamics of charge-density waves in the gas. We find that strong nearest-neighbor interactions slow down the relaxation. Our work opens the door for quantum simulations of systems with strong nonlocal interactions such as extended Fermi-Hubbard models.},
issn = {2160-3308},
doi = {10.1103/PhysRevX.11.021036},
author = {Guardado-Sanchez, Elmer and Spar, Benjamin M. and Schauss, Peter and Belyansky, Ron and Young, Jeremy T. and Bienias, Przemyslaw and Gorshkov, V, Alexey and Iadecola, Thomas and Bakr, Waseem S.}
}
@article {liu_circuit_2020,
title = {Circuit complexity across a topological phase transition},
journal = {Phys. Rev. Res.},
volume = {2},
number = {1},
year = {2020},
note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article},
month = {mar},
abstract = {We use Nielsen{\textquoteright}s geometric approach to quantify the circuit complexity in a one-dimensional Kitaev chain across a topological phase transition. We find that the circuit complexities of both the ground states and nonequilibrium steady states of the Kitaev model exhibit nonanalytical behaviors at the critical points, and thus can be used to detect both equilibrium and dynamical topological phase transitions. Moreover, we show that the locality property of the real-space optimal Hamiltonian connecting two different ground states depends crucially on whether the two states belong to the same or different phases. This provides a concrete example of classifying different gapped phases using Nielsen{\textquoteright}s circuit complexity. We further generalize our results to a Kitaev chain with long-range pairing, and we discuss generalizations to higher dimensions. Our result opens up an avenue for using circuit complexity as a tool to understand quantum many-body systems.},
doi = {10.1103/PhysRevResearch.2.013323},
author = {Liu, Fangli and Whitsitt, Seth and Curtis, Jonathan B. and Lundgren, Rex and Titum, Paraj and Yang, Zhi-Cheng and Garrison, James R. and Gorshkov, V, Alexey}
}
@article {tran_destructive_2020,
title = {Destructive {Error} {Interference} in {Product}-{Formula} {Lattice} {Simulation},
journal = {Phys. Rev. Lett.},
volume = {124},
number = {22},
year = {2020},
note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article},
month = {jun},
abstract = {Quantum computers can efficiently simulate the dynamics of quantum systems. In this Letter, we study the cost of digitally simulating the dynamics of several physically relevant systems using the first-order product-formula algorithm. We show that the errors from different Trotterization steps in the algorithm can interfere destructively, yielding a much smaller error than previously estimated. In particular, we prove that the total error in simulating a nearest-neighbor interacting system of n sites for time t using the first-order product formula with r time slices is O(nt/r + nt(3)/r(2)) when nt(2)/r is less than a small constant. Given an error tolerance epsilon, the error bound yields an estimate of max\{O(n(2)t/epsilon), O(n(2)t(3/2)/epsilon(1/2))\} for the total gate count of the simulation. The estimate is tighter than previous bounds and matches the empirical performance observed in Childs et al. [Proc. Natl. Acad. Sci. U.S.A. 115, 9456 (2018)]. We also provide numerical evidence for potential improvements and conjecture an even tighter estimate for the gate count.},
issn = {0031-9007},
doi = {10.1103/PhysRevLett.124.220502},
author = {Tran, Minh C. and Chu, Su-Kuan and Su, Yuan and Childs, Andrew M. and Gorshkov, V, Alexey}
}
@article {eldredge_entanglement_2020,
title = {Entanglement bounds on the performance of quantum computing architectures},
journal = {Phys. Rev. Res.},
volume = {2},
number = {3},
year = {2020},
note = {Place: ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA Publisher: AMER PHYSICAL SOC Type: Article},
month = {aug},
abstract = {There are many possible architectures of qubit connectivity that designers of future quantum computers will need to choose between. However, the process of evaluating a particular connectivity graph{\textquoteright}s performance as a quantum architecture can be difficult. In this paper, we show that a quantity known as the isoperimetric number establishes a lower bound on the time required to create highly entangled states. This metric we propose counts resources based on the use of two-qubit unitary operations, while allowing for arbitrarily fast measurements and classical feedback. We use this metric to evaluate the hierarchical architecture proposed by A. Bapat et al. [Phys. Rev. A 98, 062328 (2018)] and find it to be a promising alternative to the conventional grid architecture. We also show that the lower bound that this metric places on the creation time of highly entangled states can be saturated with a constructive protocol, up to a factor logarithmic in the number of qubits.},
doi = {10.1103/PhysRevResearch.2.033316},
author = {Eldredge, Zachary and Zhou, Leo and Bapat, Aniruddha and Garrison, James R. and Deshpande, Abhinav and Chong, Frederic T. and Gorshkov, V, Alexey}
}
@article { ISI:000562633900003,
title = {Exotic Photonic Molecules via Lennard-Jones-like Potentials},
journal = {Phys. Rev. Lett.},
volume = {125},
number = {9},
year = {2020},
month = {AUG 26},
pages = {093601},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {Ultracold systems offer an unprecedented level of control of interactions between atoms. An important challenge is to achieve a similar level of control of the interactions between photons. Towards this goal, we propose a realization of a novel Lennard-Jones-like potential between photons coupled to the Rydberg states via electromagnetically induced transparency (EIT). This potential is achieved by tuning Rydberg states to a Forster resonance with other Rydberg states. We consider few-body problems in 1D and 2D geometries and show the existence of self-bound clusters ({{\textquoteright}{\textquoteright}}molecules{{\textquoteright}{\textquoteright}}) of photons. We demonstrate that for a few-body problem, the multibody interactions have a significant impact on the geometry of the molecular ground state. This leads to phenomena without counterparts in conventional systems: For example, three photons in two dimensions preferentially arrange themselves in a line configuration rather than in an equilateral-triangle configuration. Our result opens a new avenue for studies of many-body phenomena with strongly interacting photons.},
issn = {0031-9007},
doi = {10.1103/PhysRevLett.125.093601},
author = {Bienias, Przemyslaw and Gullans, Michael J. and Kalinowski, Marcin and Craddock, Alexander N. and Ornelas-Huerta, Dalia P. and Rolston, S. L. and Porto, V, J. and Gorshkov, V, Alexey}
}
@article { ISI:000535205600016,
title = {Hilbert-Space Fragmentation from Strict Confinement},
journal = {Phys. Rev. Lett.},
volume = {124},
number = {20},
year = {2020},
month = {MAY 22},
pages = {207602},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {We study one-dimensional spin-1/2 models in which strict confinement of Ising domain walls leads to the fragmentation of Hilbert space into exponentially many disconnected subspaces. Whereas most previous works emphasize dipole moment conservation as an essential ingredient for such fragmentation, we instead require two commuting U(1) conserved quantities associated with the total domain-wall number and the total magnetization. The latter arises naturally from the confinement of domain walls. Remarkably, while some connected components of the Hilbert space thermalize, others are integrable by Bethe ansatz. We further demonstrate how this Hilbert-space fragmentation pattern arises perturbatively in the confining limit of Z(2) gauge theory coupled to fermionic matter, leading to a hierarchy of timescales for motion of the fermions. This model can be realized experimentally in two complementary settings.},
issn = {0031-9007},
doi = {10.1103/PhysRevLett.124.207602},
author = {Yang, Zhi-Cheng and Liu, Fangli and Gorshkov, V, Alexey and Iadecola, Thomas}
}
@article { ISI:000571399800001,
title = {Minimal Model for Fast Scrambling},
journal = {Phys. Rev. Lett.},
volume = {125},
number = {13},
year = {2020},
month = {SEP 21},
pages = {130601},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {We study quantum information scrambling in spin models with both long-range all-to-all and shortrange interactions. WC argue that a simple global, spatially homogeneous interaction together with local chaotic dynamics is sufficient to give rise to fast scrambling, which describes the spread of quantum information over the entire system in a time that is logarithmic in the system size. This is illustrated in two tractable models: (1) a random circuit with Haar random local unitaties and a global interaction and (2) a classical model of globally coupled nonlinear oscillators. We use exact numerics to provide further evidence by studying the time evolution of an out-of-time-order correlator and entanglement entropy in spin chains of intermediate sizes. Our results pave the way towards experimental investigations of fast scrambling and aspects of quantum gravity with quantum simulators.},
issn = {0031-9007},
doi = {10.1103/PhysRevLett.125.130601},
author = {Belyansky, Ron and Bienias, Przemyslaw and Kharkov, Yaroslav A. and Gorshkov, V, Alexey and Swingle, Brian}
}
@article { ISI:000575175400005,
title = {Nature of the nonequilibrium phase transition in the non-Markovian driven Dicke model},
journal = {Phys. Rev. A},
volume = {102},
number = {3},
year = {2020},
month = {SEP 23},
pages = {032218},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {The Dicke model famously exhibits a phase transition to a superradiant phase with a macroscopic population of photons and is realized in multiple settings in open quantum systems. In this paper, we study a variant of the Dicke model where the cavity mode is lossy due to the coupling to a Markovian environment while the atomic mode is coupled to a colored bath. We analytically investigate this model by inspecting its low-frequency behavior via the Schwinger-Keldysh field theory and carefully examine the nature of the corresponding superradiant phase transition. Integrating out the fast modes, we can identify a simple effective theory allowing us to derive analytical expressions for various critical exponents including the dynamical exponent. We find excellent agreement with previous numerical results when the non-Markovian bath is at zero temperature; however, contrary to these studies, our low-frequency approach reveals that the same exponents govern the critical behavior when the colored bath is at finite temperature unless the chemical potential is zero. Furthermore, we show that the superradiant phase transition is classical in nature, while it is genuinely nonequilibrium. We derive a fractional Langevin equation and conjecture the associated fractional Fokker-Planck equation that captures the system{\textquoteright}s long-time memory as well as its nonequilibrium behavior. Finally, we consider finite-size effects at the phase transition and identify the finite-size scaling exponents, unlocking a rich behavior in both statics and dynamics of the photonic and atomic observables.},
issn = {2469-9926},
doi = {10.1103/PhysRevA.102.032218},
author = {Lundgren, Rex and Gorshkov, V, Alexey and Maghrebi, Mohammad F.}
}
@article {pagano_quantum_2020,
title = {Quantum approximate optimization of the long-range {Ising} model with a trapped-ion quantum simulator},
journal = {Proc. Natl. Acad. Sci. U. S. A.},
volume = {117},
number = {41},
year = {2020},
note = {Place: 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA Publisher: NATL ACAD SCIENCES Type: Article},
month = {oct},
pages = {25396{\textendash}25401},
abstract = {Quantum computers and simulators may offer significant advantages over their classical counterparts, providing insights into quantum many-body systems and possibly improving performance for solving exponentially hard problems, such as optimization and satisfiability. Here, we report the implementation of a low-depth Quantum Approximate Optimization Algorithm (QAOA) using an analog quantum simulator. We estimate the ground-state energy of the Transverse Field Ising Model with long-range interactions with tunable range, and we optimize the corresponding combinatorial classical problem by sampling the QAOA output with high-fidelity, single-shot, individual qubit measurements. We execute the algorithm with both an exhaustive search and closed-loop optimization of the variational parameters, approximating the ground-state energy with up to 40 trapped-ion qubits. We benchmark the experiment with bootstrapping heuristic methods scaling polynomially with the system size. We observe, in agreement with numerics, that the QAOA performance does not degrade significantly as we scale up the system size and that the runtime is approximately independent from the number of qubits. We finally give a comprehensive analysis of the errors occurring in our system, a crucial step in the path forward toward the application of the QAOA to more general problem instances.},
keywords = {computing, quantum, quantum algorithms, quantum information science, quantum simulation, trapped ions},
issn = {0027-8424},
doi = {10.1073/pnas.2006373117},
author = {Pagano, Guido and Bapat, Aniruddha and Becker, Patrick and Collins, Katherine S. and De, Arinjoy and Hess, Paul W. and Kaplan, Harvey B. and Kyprianidis, Antonis and Tan, Wen Lin and Baldwin, Christopher and Brady, Lucas T. and Deshpande, Abhinav and Liu, Fangli and Jordan, Stephen and Gorshkov, V, Alexey and Monroe, Christopher}
}
@article { ISI:000550577700002,
title = {Real-time dynamics of string breaking in quantum spin chains},
journal = {Phys. Rev. B},
volume = {102},
number = {1},
year = {2020},
month = {JUL 21},
pages = {014308},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {String breaking is a central dynamical process in theories featuring confinement, where a string connecting two charges decays at the expense of the creation of new particle-antiparticle pairs. Here, we show that this process can also be observed in quantum Ising chains where domain walls get confined either by a symmetry-breaking field or by long-range interactions. We find that string breaking occurs, in general, as a two-stage process. First, the initial charges remain essentially static and stable. The connecting string, however, can become a dynamical object. We develop an effective description of this motion, which we find is strongly constrained. In the second stage, which can be severely delayed due to these dynamical constraints, the string finally breaks. We observe that the associated timescale can depend crucially on the initial separation between domain walls and can grow by orders of magnitude by changing the distance by just a few lattice sites. We discuss how our results generalize to one-dimensional confining gauge theories and how they can be made accessible in quantum simulator experiments such as Rydberg atoms or trapped ions.},
issn = {2469-9950},
doi = {10.1103/PhysRevB.102.014308},
author = {Verdel, Roberto and Liu, Fangli and Whitsitt, Seth and Gorshkov, V, Alexey and Heyl, Markus}
}
@article { ISI:000548153300005,
title = {Signaling and scrambling with strongly long-range interactions},
journal = {Phys. Rev. A},
volume = {102},
number = {1},
year = {2020},
month = {JUL 8},
pages = {010401},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {Strongly long-range interacting quantum systems-those with interactions decaying as a power law 1/r(alpha) in the distance r on a D-dimensional lattice for alpha <= D-have received significant interest in recent years. They are present in leading experimental platforms for quantum computation and simulation, as well as in theoretical models of quantum-information scrambling and fast entanglement creation. Since no notion of locality is expected in such systems, a general understanding of their dynamics is lacking. In a step towards rectifying this problem, we prove two Lieb-Robinson-type bounds that constrain the time for signaling and scrambling in strongly long-range interacting systems, for which no tight bounds were previously known. Our first bound applies to systems mappable to free-particle Hamiltonians with long-range hopping, and is saturable for alpha <= D/2. Our second bound pertains to generic long-range interacting spin Hamiltonians and gives a tight lower bound for the signaling time to extensive subsets of the system for all alpha < D. This many-site signaling time lower bounds the scrambling time in strongly long-range interacting systems.},
issn = {1050-2947},
doi = {10.1103/PhysRevA.102.010401},
author = {Guo, Andrew Y. and Tran, Minh C. and Childs, Andrew M. and Gorshkov, V, Alexey and Gong, Zhe-Xuan}
}
@article {ISI:000464756500001,
title = {Confined Quasiparticle Dynamics in Long-Range Interacting Quantum Spin Chains},
journal = {Phys. Rev. Lett.},
volume = {122},
number = {15},
year = {2019},
month = {APR 16},
pages = {150601},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {We study the quasiparticle excitation and quench dynamics of the one-dimensional transverse-field Ising model with power-law (1/r(alpha)) interactions. We find that long-range interactions give rise to a confining potential, which couples pairs of domain walls (kinks) into bound quasiparticles, analogous to mesonic states in high-energy physics. We show that these quasiparticles have signatures in the dynamics of order parameters following a global quench, and the Fourier spectrum of these order parameters can be exploited as a direct probe of the masses of the confined quasiparticles. We introduce a two-kink model to qualitatively explain the phenomenon of long-range-interaction-induced confinement and to quantitatively predict the masses of the bound quasiparticles. Furthermore, we illustrate that these quasiparticle states can lead to slow thermalization of one-point observables for certain initial states. Our work is readily applicable to current trapped-ion experiments.},
issn = {0031-9007},
doi = {10.1103/PhysRevLett.122.150601},
author = {Liu, Fangli and Lundgren, Rex and Titum, Paraj and Pagano, Guido and Zhang, Jiehang and Monroe, Christopher and Gorshkov, V, Alexey}
}
@article { ISI:000489036000001,
title = {Heisenberg-scaling measurement protocol for analytic functions with quantum sensor networks},
journal = {Phys. Rev. A},
volume = {100},
number = {4},
year = {2019},
month = {OCT 7},
pages = {042304},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {We generalize past work on quantum sensor networks to show that, for d input parameters, entanglement can yield a factor O(d) improvement in mean-squared error when estimating an analytic function of these parameters. We show that the protocol is optimal for qubit sensors, and we conjecture an optimal protocol for photons passing through interferometers. Our protocol is also applicable to continuous variable measurements, such as one quadrature of a field operator. We outline a few potential applications, including calibration of laser operations in trapped ion quantum computing.},
issn = {2469-9926},
doi = {10.1103/PhysRevA.100.042304},
author = {Qian, Kevin and Eldredge, Zachary and Ge, Wenchao and Pagano, Guido and Monroe, Christopher and Porto, V, J. and Gorshkov, V, Alexey}
}
@article { ISI:000457704900001,
title = {Interacting Qubit-Photon Bound States with Superconducting Circuits},
journal = {PHYSICAL REVIEW X},
volume = {9},
number = {1},
year = {2019},
month = {FEB 1},
pages = {011021},
issn = {2160-3308},
doi = {10.1103/PhysRevX.9.011021},
author = {Sundaresan, Neereja M. and Lundgren, Rex and Zhu, Guanyu and Gorshkov, V, Alexey and Houck, Andrew A.}
}
@article { ISI:000498063400002,
title = {Nondestructive Cooling of an Atomic Quantum Register via State-Insensitive Rydberg Interactions},
journal = {Phys. Rev. Lett.},
volume = {123},
number = {21},
year = {2019},
month = {NOV 20},
pages = {213603},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {We propose a protocol for sympathetically cooling neutral atoms without destroying the quantum information stored in their internal states. This is achieved by designing state-insensitive Rydberg interactions between the data-carrying atoms and cold auxiliary atoms. The resulting interactions give rise to an effective phonon coupling, which leads to the transfer of heat from the data atoms to the auxiliary atoms, where the latter can be cooled by conventional methods. This can be used to extend the lifetime of quantum storage based on neutral atoms and can have applications for long quantum computations. The protocol can also be modified to realize state-insensitive interactions between the data and the auxiliary atoms but tunable and nontrivial interactions among the data atoms, allowing one to simultaneously cool and simulate a quantum spin model.},
issn = {0031-9007},
doi = {10.1103/PhysRevLett.123.213603},
author = {Belyansky, Ron and Young, Jeremy T. and Bienias, Przemyslaw and Eldredge, Zachary and Kaufman, Adam M. and Zoller, Peter and Gorshkov, V, Alexey}
}
@article {ISI:000462935500003,
title = {Scale-Invariant Continuous Entanglement Renormalization of a Chern Insulator},
journal = {Phys. Rev. Lett.},
volume = {122},
number = {12},
year = {2019},
month = {MAR 27},
pages = {120502},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {The multiscale entanglement renormalization ansatz (MERA) postulates the existence of quantum circuits that renormalize entanglement in real space at different length scales. Chem insulators, however, cannot have scale-invariant discrete MERA circuits with a finite bond dimension. In this Letter, we show that the continuous MERA (cMERA), a modified version of MERA adapted for field theories, possesses a fixed point wave function with a nonzero Chern number. Additionally, it is well known that reversed MERA circuits can be used to prepare quantum states efficiently in time that scales logarithmically with the size of the system. However, state preparation via MERA typically requires the advent of a full-fledged universal quantum computer. In this Letter, we demonstrate that our cMERA circuit can potentially be realized in existing analog quantum computers, i.e., an ultracold atomic Fermi gas in an optical lattice with light-induced spin-orbit coupling.},
issn = {0031-9007},
doi = {10.1103/PhysRevLett.122.120502},
author = {Chu, Su-Kuan and Zhu, Guanyu and Garrison, James R. and Eldredge, Zachary and Curiel, Ana Valdes and Bienias, Przemyslaw and Spielman, I. B. and Gorshkov, V, Alexey}
}
@article { ISI:000439744700003,
title = {Distributed Quantum Metrology with Linear Networks and Separable Inputs},
journal = {PHYSICAL REVIEW LETTERS},
volume = {121},
number = {4},
year = {2018},
month = {JUL 25},
pages = {043604},
issn = {0031-9007},
doi = {10.1103/PhysRevLett.121.043604},
author = {Ge, Wenchao and Jacobs, Kurt and Eldredge, Zachary and Gorshkov, V, Alexey and Foss-Feig, Michael}
}